WASHINGTON – President Barack Obama appears one price-spike away from tapping crude from the U.S. emergency reserves, as political pressure drives him to assure Americans he will keep gasoline costs under control.

Obama reiterated comments from a host of his top officials Friday, saying a plan to tap the reserve was “teed up”, and vowing to move quickly should conditions worsen.

With the potential for further upheaval in the Middle East, plus the possibility of a demand shock if Japan rapidly steps up imports after an earthquake damaged its refineries and nuclear power plants, Obama may have the excuse he needs to come to the aid of voters scared about escalating costs.

The administration is already “war gaming” the impact accessing the reserve would have on prices, and is in talks with the Paris-based International Energy Agency, a Congressional aide told Reuters.

Further escalation from the current $100-a-barrel level, and signs of a long-term supply disruption, would likely seal the deal as pressure mounts from Democrats including Jeff Bingaman, chairman of the Senate Energy and Natural Resources Committee, and his colleague Jay Rockefeller.

Obama refused to say what price could trigger a release, but many expect one to come sooner rather than later if fuel prices keep rising. Gasoline now is $3.54 a gallon following the biggest two-week rise since Hurricane Katrina.

“It would be difficult for the administration to stand by and watch gasoline go up another 25 or 35 cents,” said Guy Caruso, who headed the federal Energy Information Administration when then-President George W. Bush sold oil from the SPR after Katrina in 2005.

“They would probably do something. There would be oil made available from the SPR,” said Caruso, now an energy advisor at the Center for Strategic and International Studies.

Oil would fall $5 to $10 a barrel in the short term if the SPR were tapped, he said, and gasoline prices would probably drop about 24 cents a gallon.

One option could be pushing forward a previous proposal under the White House’s 2011 budget seeking Congressional approval to sell $500 million of oil — about 5 million barrels — from the reserve to pay for maintenance.

“Just offer up that 5 million and empty that cavern,” Caruso said. “This might be killing two birds with one stone.”

Prices remain well below the record $147 a barrel hit in 2008, when fast-growing demand, years of underinvestment in the sector and a surgeutput from oil-producing nations.

Saudi Arabia has pumped more oil to make up for the loss of nearly all of Libya’s 1.6 million barrels per day. But that has had little effect on prices the U.S. government now forecasts will average a record above $100 in 2011.

With 727 million barrels of crude, enough to meet U.S. crude import demand for about 78 days, the SPR is a powerful tool, but one that has been used sparingly.

Previous administrations mostly used the reserve as a bank, with loans of crude to refiners to cool prices after immediate needs arose from hurricanes, ship channel closures, or during cold winters in the Northeast. Those loans were repaid once markets normalized.

More rare have been major sales from the SPR, which have been used twice since the government set up the reserve after the 1973 Arab oil embargo: then-President George W. Bush sold oil after Katrina, and his father George H. W. Bush sold it after Iraq’s 1990 to 1991 invasion of Kuwait.

After the Katrina sale, gasoline fell 28 cents a gallon, or 10 percent, in two weeks. But unlike Katrina — when the SPR helped cover a temporary crippling of U.S. refineries — the market now faces a likely long-term loss of Libyan crude, coupled with the open-ended risk of regional unrest infecting other big producers.

As a result, not everyone believes tapping the SPR is the right course. Most Republican lawmakers stand against it, short of a significant national emergency. Releasing the oil also carries risks. If traders interpret the move as a sign violence in the Middle East and North Africa could worsen, prices may go higher before moving down.

But Obama, increasingly on an election footing, also has political risks to manage. Releasing reserves would show him taking an active role instead of relying on producers.

A Reuters/Ipsos poll showed on Wednesday that the proportion of Americans who believe the country is on the wrong track rose 7 percentage points to 64 percent from February.

In many ways, Obama’s energy policy of moving to efficient cars and alternative fuels has benefited from higher oil prices. But failing to address rising fuel costs for millions of voters with at least an SPR loan could be a misstep ahead of the 2012 elections.

“It sure seems like good politics to act in a way that appears responsive to voters’ primary concerns,” said Kevin Book, an analyst at ClearView Energy Partners LLC in Washington.